1. Field of the Invention
The present invention relates to image pickup apparatuses and methods for controlling the same. In particular, the present invention relates to an image pickup apparatus capable of picking up moving images and still images and a method for controlling the image pickup apparatus.
2. Description of the Related Art
Many of image pickup apparatuses using a photoelectric conversion element (such as a charge-coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor) as an image pickup element are capable of selectively picking up still and moving images and performing an image pickup operation according to the user's preference.
Such image pickup apparatuses typically require the user to pre-select either a mode (still image mode) for picking up still images or a mode (moving image mode) for picking up moving images.
There are some image pickup apparatuses in which, when a button for picking up still images is pressed during a moving-image pickup operation, the image pickup mode switches from a moving image mode to a still image mode which enables a still-image pickup operation. However, since a moving image picked up during switching from the moving image mode to the still image mode is lacked and discontinuously recorded, the resulting moving image does not look natural when reproduced.
There is proposed an image pickup apparatus which allows quick switching to a still image mode so as to minimize lacking of a moving image during switching to the still image mode. However, when the switching is done quickly, the timing to release a shutter for still-image pickup may be off. In this case, a recovery process is performed to generate a still image from a picked-up moving image. However, since the number of pixels constituting a moving image is smaller than the number of pixels constituting a still image, the quality of the still image generated from the moving image is not satisfactory.
Additionally, in this case, the operation of an aperture mechanism for controlling an incident light quantity is not quick enough to respond to the quick mode switching. Practically, this means that it is not possible to change the shutter speed, and thus, exposure time for a still-image pickup operation is made the same as that for a moving-image pickup operation. As a result, when an image of a moving subject is picked up, the resulting image may suffer from blurring.